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Calf injuries not involving the Achilles tendon

Calf injuries not involving the Achilles tendon
Literature review current through: Jan 2024.
This topic last updated: Aug 25, 2021.

INTRODUCTION — Posterior calf injuries are common and occur in both competitive and recreational athletes as well as active laborers. The major posterior calf muscles include the gastrocnemius, soleus, popliteal, and plantaris muscles. These muscles primarily perform active plantarflexion of the ankle and are typically injured during ballistic movements. Patients with posterior calf injuries present with limping, swelling of the posterior calf, and significant pain at the time of injury.

This topic will review common and important posterior calf injuries, including the mechanisms of injury, diagnosis, and management. Achilles tendon and other leg injuries are discussed separately. (See "Achilles tendinopathy and tendon rupture" and "Ankle sprain in adults: Evaluation and diagnosis" and "Ankle fractures in adults".)

EPIDEMIOLOGY AND RISK FACTORS — Muscle strains of the posterior calf affect both competitive and recreational athletes but occur most often in poorly conditioned male athletes in the fourth to sixth decade of life [1-4]. Calf injuries typically occur during sudden ballistic movements involving the lower extremity, such as sprinting or jumping, in sports or activities where these movements are common, such as tennis, football (soccer), basketball, American football, running up hills, and some types of military training [1,5]. The medial head of the gastrocnemius in particular plays a major role in generating power when athletes jump or sprint, and injuries of the medial head are relatively common. Calf muscle strains usually occur when the muscles are not warmed up properly or have fatigued significantly during exercise. Approximately 20 percent of patients report prodromal symptoms including soreness or tightness in their calf muscle prior to the injury [2].

Competitive male masters runners, defined as older than age 40, are at higher risk for calf injuries. Survey studies from races reveal that calf injury is among the most common injuries for all male runners and disproportionately affects older runners [6,7]. As an example, a six year study of the Taroko Gorge Marathon found that 34 percent of male recreational runners who sought physical therapy at the end of the race had sustained a calf injury, compared to 28 of women [8].

Runners with a forefoot strike pattern may be at an increased risk for gastrocnemius injury. Computer simulation studies report that a forefoot strike pattern increases overall work (and thereby injury risk) for the gastrocnemius muscles while decreasing soleus muscle work [9].

Calf injuries are common among tennis players [10]. A case series of medial calf injury in 720 athletes found that 16 percent arose from tennis [11]. A large proportion of such injuries occur at the musculotendinous junction of the medial head of the gastrocnemius muscle or the aponeurosis between the medial gastrocnemius and soleus muscles [11]. These injuries are often referred to as "tennis leg." For patients diagnosed with tennis leg, only 14 percent of injuries occur at the lateral head of the gastrocnemius [12], and 1.4 percent involve plantaris rupture [11].

The frequency of calf injury appears to be increasing in certain sports. As an example, calf injury now ranks as the second most common muscle injury in Australian-rules football [13]. In this population, the soleus was affected more often (62 percent) than the gastrocnemius (24 percent), but the location of injury remained consistent with other calf muscle strains, as 84 percent of soleus injuries occurred at the musculotendinous junction. By contrast, a study of United States professional football players reported that 74 percent of calf injuries involved the gastrocnemius and 15 percent the soleus [14].

While most studies report a preponderance of gastrocnemius injuries, calf injury location likely differs with the demands of a given sport. According to one observational study using magnetic resonance imaging (MRI), ultrasound, the imaging technique used most often to assess calf injuries, may underdiagnose deeper soleus strains, thereby introducing a measurement bias that exaggerates the number of calf injuries attributed to gastrocnemius strain [15].

The literature pertaining to risk factors for calf injury is limited. A history of a posterior calf strain is a risk factor for recurrent injury [4,16,17]. Among older soccer players, a history of a lumbar entrapment of the fifth lumbar (L5) nerve root has been associated with an increased risk for posterior gastrocnemius strain, and this condition may be a risk factor for other active adults [18]. A systematic review noted that increasing age and previous calf strain are most predictive of future calf injury [4]. Older age is associated with an increased risk of calf injury in many sports besides running. For elite soccer (football) athletes, the frequency of calf injury increases as players age, starting at age 23 [19].

While most calf injuries relate to sport, there are case reports of gastrocnemius injuries occurring in older, deconditioned adults at work, including jobs that require frequent loading or sudden stretching of the calf [20]. Bilateral, medial gastrocnemius ruptures have occurred after prolonged walking in high heels. Other medical factors associated with calf tendon injury include fluoroquinolones, glucocorticoids, chronic kidney disease, and lupus and other diseases affecting connective tissue [21].

CLINICAL ANATOMY AND BIOMECHANICS — The anatomy of the calf includes several overlapping muscles and tendons (picture 1A-C and figure 1) [22,23]. The medial head of the gastrocnemius originates at the posterior surface of the medial femoral condyle, while the lateral head originates at the lateral femoral condyle (picture 2). The two heads of the gastrocnemius have considerable proximal muscle bulk and are separated by an intramuscular septum. The proximal gastrocnemius is thinner, and the superficial fibers form a fascial aponeurosis. The gastrocnemius contains both slow- and fast-twitch muscle fibers. Innervation of the gastrocnemius is from the tibial nerve and primarily the first sacral (S1) nerve root, with some contribution from the fifth lumbar (L5) nerve root.

The soleus muscle originates at the mid portion of the proximal posterior tibia, the posterior fibular head, and the proximal third of the fibular shaft (picture 3). This flat and broad muscle extends distally to approximately 10 to 15 cm above the calcaneus, where its fibers narrow into a deep aponeurosis and merge with those of the more superficial gastrocnemius aponeurosis to form the true tendinous portion of the Achilles tendon. Within the proximal soleus, there are intramuscular tendons that separate distinct muscle bundles. According to some anatomists, the soleus and two heads of the gastrocnemius represent a single muscle unit that is sometimes called the triceps surae. Innervation is from the tibial nerve and nerve roots from L4 to S2.

The soleus muscle contains primarily slow-twitch muscle fibers. Thus, while the gastrocnemius accounts for most of the power generated by the calf for speed and jumping, the soleus plays a major role in maintaining strength and endurance for prolonged or repeated plantar flexion during activity. The most common accessory muscle in the leg is an accessory soleus muscle (0.7 to 5 percent according to autopsy reports), which can take a variety of forms, interposing between the distal main soleus muscle and the Achilles tendon. On imaging studies, the accessory soleus manifests as increased muscle tissue behind the medial malleolus and extending to the calcaneus [24].

The plantaris muscle originates at the lateral supracondylar line, which is a small ridge of bone along the posterior half of the lateral femoral condyle, just proximal to the origin of the lateral head of the gastrocnemius (picture 4). Some fibers may originate from the oblique popliteal ligament. In most individuals, the small muscle belly extends only 5 to 10 cm distally before becoming a long, thin tendon that travels in a plane between the medial gastrocnemius and the soleus. This tendon inserts along the medial aspect of the Achilles tendon about 5 to 7 cm proximal to the calcaneus, although it sometimes extends to the medial calcaneus [11,25]. Some anatomists feel the plantaris is a vestigial muscle with no functional role, while others feel that it provides some assistance during plantar flexion and may weakly assist knee flexion. Innervation is from the tibial nerve and nerve roots from L5 to S2.

The popliteal muscle has three origins: the lateral femoral condyle, fibula, and lateral horn of the meniscus. The muscle then travels deep to the lateral collateral ligament off of the lateral femoral condyle and through the popliteal hiatus, inserting onto the posterior aspect of the proximal tibia. The popliteal muscle internally rotates the tibia against the femur and prevents external rotation of the tibia [26].

A neurovascular bundle, containing the popliteal artery, popliteal vein, and tibial nerve, emerges above the knee close to the hiatus of the adductor magnus muscle and passes into the popliteal space (picture 5). The nerve and vessels pass deep through a fibrous arc in the proximal soleus to lie along the posterior surface of the tibia. Branches of the tibial nerve and the popliteal artery supply each of the major muscles and structures of the posterior knee and proximal calf (figure 2 and figure 3). In some individuals, anatomic anomalies or repetitive trauma may result in compression of the vessels in the popliteal space. Of note, the calf has a rich vascular supply, and any significant tissue trauma can lead to prolonged intramuscular bleeding.

The sural nerve is formed from the branches of the tibial nerve and the common peroneal nerve in the posterior calf. The sural nerve provides sensory innervation of the posterior lateral calf and can be injured in conjunction with damage to the lateral head of the gastrocnemius muscle.

MECHANISM OF INJURY AND CLINICAL PRESENTATION

Gastrocnemius strain — Gastrocnemius injuries consist primarily of sudden muscle tears that are sustained during ballistic movements involving eccentric loading of the muscle [1,2,27]. This typically occurs during a sudden push-off when an athlete initiates a sprint or jump, at which point the ankle rapidly changes from a plantarflexed position to a dorsiflexed position while the knee is fully extended or, in some situations, hyperextended. As an example, gastrocnemius strain occurs commonly in tennis players when they suddenly change directions to return a shot, which is why the term "tennis leg" is often applied to a medial head gastrocnemius injury [27].

Patients with a gastrocnemius strain typically describe feeling a sudden tearing sensation or pop accompanied by acute pain in the proximal posterior calf that developed while they were running or jumping [1,2,27]. Patients have difficulty bearing weight and prefer to keep their ankle in plantarflexion and walk on their toes without moving the ankle so as to minimize discomfort. There may be intermittent cramping, which is worse with attempts at weightbearing.

With severe strains, inspection of the patient's posterior calf often shows significant swelling and ecchymosis [1,2,27]. Palpation of the proximal calf reveals significant tenderness, usually over the medial head of the gastrocnemius, and possibly a defect in the muscle belly. Active plantar flexion and passive dorsiflexion of the ankle elicit pain in the calf. The patient is unable to perform a single leg calf raise, but the Thompson squeeze test (performed to rule out Achilles tendon rupture) is negative (picture 6).

Plantaris strain and tendon injury — Plantaris strains occur primarily with eccentric loading of the plantaris muscle that occurs during forceful dorsiflexion of the ankle while the knee remains in extension [2,28]. This movement typically happens when an athlete initiates a rapid change in direction with a forceful push-off, as occurs in basketball with jumping and pivoting or in tennis when lunging to make a shot. Up to 74 percent of athletes with these injuries may have associated findings of Achilles injury [29].

The examination findings of the patient with a plantaris muscle strain are similar to those of the patient with a gastrocnemius strain, including slight swelling, tenderness, and difficulty weightbearing [11,28,30]. However, symptoms are generally less severe (in part because the plantaris plays a relatively minor functional role and has a limited vascular supply that produces less bleeding with injury) [11]. With a plantaris strain, pain and tenderness are located in the region around the mid-Achilles tendon rather than the proximal calf, and no muscle or tendon defect is palpable. Most patients can dorsiflex and plantarflex their ankle without significant discomfort. The Thompson squeeze test is negative (picture 6).

The plantaris tendon travels in a plane between the medial head of the gastrocnemius and the soleus, inserting on the medial Achilles tendon approximately 5 to 7 cm above the calcaneus. The plantaris tendon can tear partially or completely at any point along its length [28]. Most plantaris tendon injuries produce pain deep in the calf that lasts for only a few days.

Soleus strain — Soleus strains develop when the ankle is passively dorsiflexed while the knee is flexed, as occurs during landing when running uphill [2]. Soleus strains are usually chronic injuries that develop from overuse, primarily in distance runners. Patients complain of the insidious onset of deep soreness throughout the entire posterior calf. There are no palpable muscle defects. Pain is elicited by flexing the knee and dorsiflexing the ankle simultaneously. Patients with more severe strains have pain with passive testing of the same movements. For those with a suggestive history but unimpressive static examination, performing repetitive heel raises on a step while maintaining the knees in 20 degrees of flexion isolates the soleus muscle and often elicits tightness or pain deep in the calf.

The much less common acute presentation of a soleus strain typically involves a fatigued distance runner who feels pain deep in the calf while running up a hill toward the end of a long run.

Popliteus tendinopathy — Popliteal tendinopathy is usually an overuse injury seen in downhill running and walking [31]. In sprinting or downhill running, the popliteal muscle and tendon act to decelerate forward translation of the knee and excessive tibial rotation.

Pain from popliteal tendinopathy may present as acute or chronic posterolateral knee pain made worse by walking or running downhill [31]. Pain can often be elicited by placing the affected leg in a figure-of-four position and palpating the origin of the popliteal tendon just anterior to the lateral femoral condyle. In addition, the Garrick test may be used to elicit pain from popliteal tendinopathy. In this test, the patient lies supine with their knees and hips flexed to 90 degrees. The test is positive if resisted internal rotation of the knee or passive external rotation of the knee elicits pain at the popliteal tendon. Although a positive Garrick test is suggestive, its accuracy is unknown.

The popliteal tendon assists other structures in the posterolateral corner in stabilizing the lateral knee. Tears of the popliteal tendon are rare but can occur when a direct blow forces the knee into a varus position (ie, blow to the inside of the knee), as might occur from a tackle in American football or rugby [32,33]. With severe blows, partial or complete tendon tears have been reported [34].

Popliteal artery entrapment — Popliteal artery entrapment occurs most often due to a congenital anomaly that causes the medial or lateral gastrocnemius head to shift toward the popliteal artery during knee flexion, thereby compressing the artery [1,35,36]. It is seen primarily in young active men (mean age 30 years) and therefore is not associated with an increased risk of cardiovascular disease. Multiple case reports document this condition in bicyclists, military personnel in active training, and runners [37-39]. The cause appears to be repetitive overuse that gradually causes pathological thickening of vessel walls in the popliteal artery as a response to excessive pressure from the muscle belly. In bicyclists, the injury appears to be associated with repetitive knee flexion during extended rapid pedaling.

The patient with popliteal artery entrapment typically complains of pain deep in the calf that develops only after an intense workout involving repeated ankle dorsiflexion and plantarflexion (eg, cycling, running, marching up and down hills). These symptoms may resemble those of calf claudication. During exercise, the patient may experience paresthesias across the proximal posterior calf, while immediately following exercise, he or she may notice a pale, discolored foot and toes. At all other times, the patient typically has no pain, and the examination at rest is normal. Hypertrophied calf muscles may be noted. (See "Clinical features and diagnosis of lower extremity peripheral artery disease", section on 'Claudication'.)

Assessment of distal pulses is a key part of the examination for this condition. Palpate the lower extremity pulses (dorsalis pedis and posterior tibialis) to determine whether they are diminished at baseline; it is often helpful to compare the affected and unaffected limbs. Then, palpate the pulses while the patient performs active plantarflexion and passive dorsiflexion of the ankle, while the knee remains in extension. One helpful examination technique is to have the patient stand on a step in the examination room and perform heel raises, repeatedly raising and lowering his foot above and below the level of the step, while the clinician palpates the distal pulses. The presence of a decreased pulse during such maneuvers suggests the diagnosis.

Bedside testing is often helpful for assessing pulses [36,40]. In experienced hands, dynamic Doppler ultrasound has been found to correlate closely with surgical findings, and in some institutions, it is used as a definitive diagnostic test for popliteal artery entrapment [41]. Advanced imaging such as angiography may be needed (image 1). The ankle-brachial index is low with significant compromise of arterial flow [42]. Exercise testing may be used to help establish the diagnosis. (See "Noninvasive diagnosis of upper and lower extremity arterial disease", section on 'Ankle-brachial index' and "Noninvasive diagnosis of upper and lower extremity arterial disease", section on 'Exercise testing'.)

During the examination, the popliteal artery should be palpated for an aneurysm. Popliteal aneurysm is extremely rare in young individuals, although pseudo-aneurysms have been associated with trauma to the popliteal fossa and can be delayed in presentation. Popliteal aneurysm is relatively common in older men, and in an older athlete with a history and symptoms suggesting popliteal artery entrapment, a careful assessment to exclude aneurysm, possibly including ultrasound, is needed [43]. (See "Popliteal artery aneurysm".)

Rupture of accessory soleus tendon — Accessory soleus muscles occur in up to 5 percent of individuals. They attach to the superior or medial calcaneus or to the Achilles tendon. Attachments can be true tendons or fibromuscular insertions, and both types can rupture. Case reports describe accessory soleus tendon rupture presenting as distal, posterior-medial calf pain. Ultrasound and magnetic resonance imaging (MRI) both demonstrate the rupture, retraction of fibers, and swelling of surrounding tissue [24].

DIAGNOSTIC IMAGING — Neither plain radiographs nor advanced imaging is typically needed to assess muscle strains or tendinopathy of the calf, but ultrasound is useful for confirming the diagnosis and assessing the extent of injury. Advanced imaging is needed to diagnose popliteal artery entrapment.

Musculoskeletal injury

Plain radiographs — Plain radiographs are typically not needed when the diagnosis of a muscle injury is reasonably certain based upon the history and physical examination and no other significant injuries are suspected. When the diagnosis is not certain and other injuries (particularly fractures) are possible, most clinicians obtain plain radiographs of the tibia, fibula, and knee. For patients with pain involving the distal leg and calf, radiographs of the ankle may also be needed. These studies may reveal bony abnormalities and can rule out most fractures and calcific tendinosis.

Ultrasound — Ultrasound is widely used by knowledgeable clinicians to assess musculoskeletal injuries. The ultrasound findings associated with specific calf muscle and tendon injuries are well described [2,11,22,44-48].

With gastrocnemius tears, ultrasound shows disruption of the normal fiber alignment, typically at the musculotendinous junction, and a hematoma and fluid collection (image 2 and image 3 and image 4 and image 5) [2,3,11,44,48]. The fluid collection is anechoic (ie, appears black) and is seen between the aponeurosis of the medial head of the gastrocnemius and the soleus muscle (image 6). The fluid collection typically becomes larger over the course of the first week following injury. The examiner can repeat the ultrasound in two to three weeks to assess healing if patient symptoms and function are not progressing as expected. The examiner can also compare the affected and unaffected legs. Healing typically starts at the periphery and progresses towards the center of the tear [3,11].

Plantaris muscle tears most often occur deep to the intersection of the medial and lateral head of the gastrocnemius muscles in the mid-posterior calf. An ultrasound probe placed in a longitudinal position may reveal a small hypoechoic defect that lies in the plane between the medial head of the gastrocnemius and the soleus. Sometimes, the retracted plantaris tendon can be visualized. A less common location for a plantaris tear is along the medial border of the Achilles tendon, about 5 cm proximal to the calcaneal insertion, where the plantaris tendon merges with the Achilles. These tears appear as a discrete hypoechoic swelling located at the Achilles tendon border and are often better visualized with ultrasound images in the transverse plane [11,17,49].

With the exception of extremely obese individuals, ultrasound can usually identify the large majority of acute or chronic soleus muscle injuries [22,49]. In acute injury, a small focal tear or localized region of hypoechoic change in the muscle typically is found at the area of maximal tenderness in the calf. Chronic soleus strain causes generalized hypoechoic change throughout the muscle. Increased Doppler flow or the presence of neovessels suggests acute inflammation [2]. Some investigators have found that ultrasound is much less sensitive for soleus injury than magnetic resonance imaging (MRI), but this may be related to the timing of the scan and the quality of the study [50]. Ultrasound is useful for identifying accessory soleus tendon ruptures [24].

Ultrasound can be used to assess a number of other calf injuries. As an example, popliteal tendinopathy can be seen as a tendon with surrounding hypoechoic fluid on a transverse image of the tendon ("bulls-eye" appearance) as it passes through the popliteal groove [51]. Splits in the tendon may be seen by using a longitudinal probe position at the posterolateral joint line. If the tendon cannot be visualized in the popliteal groove, this suggests that the ruptured tendon is retracted.

Advanced imaging — In the United States, MRI is the gold standard for imaging the soft tissue, as it can assess multiple muscles at once as well as the Achilles tendon. However, MRI is only necessary if the diagnosis is unclear clinically [2]. Computed tomography (CT) is not typically used to image soft tissue calf injuries.

In professional sport, MRI is playing an increasing role as a tool for helping to determine when an athlete can return to play. MRI patterns that suggest a prolonged recovery following calf injury include involvement of multiple muscles, deep tissue injury involving the soleus, large fascial defects, and tears at a musculotendinous junction [13,14]. The area of muscle damage found on MRI can vary with the timing of the scan and does not correlate clearly with the time needed for return to play. One prospective observational study reported that extension of edema on MRI suggests a slower return from soleus injury [15].

In one retrospective study of 100 consecutive athletes with 114 calf muscle tears, MRI findings of connective tissue injury correlated closely with the time required for return to play [52]. Athletes were rated from 0 (no connective tissue injury) to 3 (complete disruption). Those with a grade 0 injury returned to play in eight days, grade 1 in 17 days, grade 2 in 25 days, and grade 3 in 48 days. These results suggest that damage to the connective tissue may prove to be highly predictive of time needed for return to play. One limitation of MRI studies is that most focus on elite athletes, and results may not be generalizable to recreational athletes and others.

Neurovascular injury — If clinical findings suggest the diagnosis of popliteal artery entrapment, magnetic resonance arteriography or standard arteriography are used in many centers to make a definitive diagnosis. Case series suggest that CT angiography correlates well with surgical findings, and some centers use this approach. A few centers have sufficient experience with ultrasound in diagnosing popliteal artery entrapment that they use this as their primary diagnostic option [41,53,54].

Emergency imaging and management are required for patients with signs of acute arterial occlusion at rest or progressively severe symptoms. Such patients usually have another cause for their arterial compromise (eg, thrombosis, dissection, aneurysm) other than popliteal artery entrapment.

DIAGNOSIS

Gastrocnemius strain — Gastrocnemius strain is diagnosed clinically on the basis of the history, typically of an acute injury to the posterior proximal calf sustained during a sudden push-off when the athlete was initiating a sprint or jump, and characteristic examination findings, including ecchymosis, swelling, and focal muscle tenderness at the proximal calf, difficulty with weightbearing, and increased calf pain with passive dorsiflexion or active plantarflexion of the ankle [1-3,11,27]. Ultrasound imaging is helpful for confirming the diagnosis and determining the extent of tear. In rare instances, magnetic resonance imaging (MRI) is performed to make a definitive diagnosis.

Plantaris strain — Plantaris rupture is diagnosed clinically on the basis of the history and examination findings, which are similar to those of a gastrocnemius strain but notably less severe and focused in a different location [11,30]. Pain and tenderness are located in the mid-Achilles region rather than the proximal calf. Unlike gastrocnemius injuries, patients usually have full range of motion of the ankle without significant pain. When patients present after a delay of a few days, those who have only limited functional impairment are more likely to have sustained a plantaris than a gastrocnemius injury. Ultrasound can be used to confirm the diagnosis. In rare instances, MRI may be performed to make a definitive diagnosis.

Soleus strain — The diagnosis of a soleus strain is generally made clinically on the basis of the history, examination, and possibly ultrasound findings. Soleus strains typically develop from overuse involving distance running; the patients complain of insidious, diffuse pain deep in the calf; pain increases when the knee is flexed and the ankle is dorsiflexed simultaneously (eg, running up a hill). If the strain is more distal and medial, consider a possible accessory soleus strain. Ultrasound can confirm the diagnosis [2,11]. In the unusual instance when the clinical presentation is unclear and a definitive diagnosis is needed, an MRI is obtained.

Popliteal tendinopathy — Popliteal tendinopathy is diagnosed clinically on the basis of a suggestive history, examination findings, and ultrasound evaluation [31]. The typical patient is a runner who has been doing speed or downhill running and complains of lateral knee or proximal posterolateral calf pain. Symptoms can often be reproduced by having the patient run downhill or sprint with an exaggerated stride length. Examination of the knee often reveals pain at the origin of the popliteal tendon when the leg is placed in a figure-of-four position and a positive Garrick test. The remainder of the knee examination is unremarkable. Ultrasound can help to confirm the diagnosis.

Popliteal artery entrapment — Definitive diagnosis of popliteal artery entrapment requires advanced imaging with magnetic resonance arteriography, computed tomography (CT) arteriography, or standard arteriography. In some hospitals, Doppler ultrasound is used to make the diagnosis. The diagnosis is suggested by a history of claudication-type symptoms brought on by intense exercise requiring repeated dorsiflexion and plantarflexion of the ankle, but which improve with rest. During exercise, the patient may experience paresthesias and cold feet or toes. During passive dorsiflexion or active plantarflexion of the ankle (performed with the knee in extension), distal pulses are often diminished [35,36]. (See "Noninvasive diagnosis of upper and lower extremity arterial disease", section on 'Ankle-brachial index'.)

INDICATIONS FOR SURGICAL CONSULT OR REFERRAL — Surgery for an isolated posterior calf muscle injury is rarely necessary. Suspicion of an acute compartment syndrome warrants immediate orthopedic consultation. Vascular surgery consultation is needed for popliteal artery entrapment. Sural nerve entrapment may require surgical intervention to remove pressure on the nerve if conservative therapy fails.

DIFFERENTIAL DIAGNOSIS — The differential diagnosis for posterior calf injuries can be divided into musculoskeletal and non-musculoskeletal categories:

Musculoskeletal

Achilles tendinopathy – Patients with noninsertional Achilles tendinopathy present with gradually increasing pain located approximately 2 to 6 cm proximal to the Achilles tendon insertion onto the calcaneus. The pain is usually associated with an increase in exercise or athletic training; the discomfort, often described as a burning sensation, increases with activity and improves with rest. Examination of the prone patient reveals focal tenderness of the tendon 2 to 6 cm from the Achilles insertion with no palpable muscle or tendon defects. The history and the location of pain and tenderness are typically sufficient to distinguish Achilles tendinopathy from calf muscle strains. Imaging with ultrasound or magnetic resonance imaging (MRI) can be helpful in the diagnosis of acute tendinopathy, but neither is as sensitive for chronic tendinopathy (symptoms lasting over three months). (See "Achilles tendinopathy and tendon rupture".)

Achilles tendon tear – Acute Achilles tendon rupture typically occurs in middle-aged adults during recreational sports when they suddenly change direction or accelerate (eg, jump, sprint). These patients often feel as if they were hit in the back of the calf and occasionally hear a "pop." Pain ranges from mild to severe. Examination reveals a palpable tendon defect and tenderness at the site of the tear. Most patients with complete tears cannot plantarflex their ankle, but clinicians must be cautious because some patients are able to plantarflex using accessory muscles. The Thompson squeeze test is positive in most complete tears (picture 6). In the great majority of cases, the clinical presentation and examination findings are sufficient to distinguish Achilles tendon tear from calf muscle injury. Ultrasound or MRI can be used for definitive diagnosis. (See "Achilles tendinopathy and tendon rupture".)

Acute compartment syndrome – Acute compartment syndrome (ACS) most often presents with rapidly progressive leg pain following trauma (although many nontraumatic causes exist). Although the accuracy of the examination is limited, common symptoms and signs include pain out of proportion to the injury, a tense swollen muscle compartment, and increased pain when the muscles in the affected compartment are stretched. Immediate surgical consultation should be obtained if ACS is suspected. (See "Acute compartment syndrome of the extremities".)

Chronic exertional compartment syndrome – Chronic exertional compartment syndrome (CECS) typically presents in young athletes, often runners, who describe gradually increasing pain in a specific region of the leg, often deep within the calf or shin, during exertion. Pain is often bilateral, generally begins within several minutes of starting the inciting activity, and resolves within 10 to 20 minutes of stopping. The pain may be accompanied by paresthesias of the foot and ankle. Examination at rest is often unremarkable in contrast to patients with acute calf muscle strains. CECS is diagnosed definitively by measuring intracompartmental pressures. (See "Chronic exertional compartment syndrome".)

Exercise associated muscle cramps – Muscle cramps develop during or shortly after exercise in recreational and competitive athletes [55]. Patients present with acute pain, stiffness, and visible bulging or knotting of the muscle. Symptoms are usually transient but may last for hours, and significant soreness can persist for days in the affected muscle. Most muscle cramps in the calf involve the gastrocnemius muscle, but even severe muscle cramps do not produce the swelling or discoloration seen with significant gastrocnemius strains. Passive dorsiflexion improves the pain associated with a muscle cramp, while it exacerbates the pain associated with a muscle strain. (See "Exertional heat illness in adolescents and adults: Epidemiology, thermoregulation, risk factors, and diagnosis", section on '"Heat cramps" (exercise associated muscle cramps)'.)

Medial tibial stress syndrome ("shin splints") – Medial tibial stress syndrome (MTSS) presents as a dull aching pain along the posterior aspect of the medial tibial shaft that increases with activity and improves with rest. It is caused by excessive performance of repetitive athletic activities such as running and jumping. Although there are no focal areas of leg tenderness with MTSS, careful palpation may reveal some tenderness along the posterior tibialis muscle and tendon distally but not other muscle groups. Performing heel raises or walking on toes typically does not cause pain with MTSS but does with calf muscle strains. (See "Running injuries of the lower extremities: Patient evaluation and common conditions", section on 'Medial tibial stress syndrome (shin splints) and tibial stress fractures'.)

Osteomyelitis – Osteomyelitis typically causes localized dull bone pain of insidious onset that does not resolve with rest. Localized warmth, erythema, and swelling, and constitutional symptoms such as fevers and chills may be present. Infection may have spread from adjacent soft tissue or an open fracture, and clinicians should inquire about such history. If suspected, osteomyelitis requires a careful workup and appropriate consultation. (See "Nonvertebral osteomyelitis in adults: Clinical manifestations and diagnosis".)

Avulsion fracture of medial gastrocnemius While rare, avulsion fracture of the femoral origin of the medial gastrocnemius muscle occurs in both the skeletally immature and mature. Case reports describe significant trauma and concomitant injuries to ligaments and associated structures. This injury should be considered in the patient with major trauma and findings that mimic the swollen calf and tenderness more typical of medial gastrocnemius injury. The injury is typically visible on a lateral knee plain radiograph, or on computed tomography (CT) or MRI if these are performed [56].

Non-musculoskeletal

Claudication — Claudication typically occurs in older patients with peripheral artery disease who present with leg pain (often in the calf) that is exacerbated by exercise in a reproducible fashion (ie, exercise of similar intensity consistently elicits symptoms) and relieved by rest, although in some cases, pain may be atypical. Distal lower extremity pulses are usually diminished, as is the ankle brachial index. Symptoms and signs may not differ from those of popliteal artery entrapment. Factors that favor the diagnosis of claudication include age over 50, risk factors for cardiovascular disease (particularly a smoking history), and stigmata of cardiovascular disease (eg, hypertension, bruits, diminished pulses in multiple extremities). (See "Clinical features and diagnosis of lower extremity peripheral artery disease".)

Deep vein thrombosis — Deep vein thrombosis (DVT) presents with worsening pain and swelling in the posterior calf. Usually, there is no history of activity to suggest acute muscle injury, although there are a few case reports of DVT developing following a calf injury sustained during intense physical activity [57-59]. The presence of risk factors for venous thrombosis (eg, recent trauma or surgery, history of prior DVT or cancer, coagulopathy, pregnancy), more generalized swelling than typically occurs with an acute calf muscle strain, and the absence of any specific area of focal tenderness all suggest DVT. DVT is potentially life-threatening, and an appropriate workup must be performed if the diagnosis is suspected. (See "Clinical presentation and diagnosis of the nonpregnant adult with suspected deep vein thrombosis of the lower extremity".)

Peripheral nerve entrapment — Swelling following trauma, hypertrophied muscle, ganglions, or other lesions can place pressure on peripheral nerves, causing the symptoms associated with nerve entrapment. The absence of a history of acute injury, or the physical findings associated with injury such as swelling and ecchymosis, helps to distinguish entrapment from gastrocnemius and other calf muscle strains. Rarely, nerve entrapments cause tenderness to palpation, but the pain elicited tends to be neuropathic (eg, sharp, tingling) and associated with distal radiation. The paresthesias and pain that increase with physical activity may improve with rest.

The two nerve entrapments that most commonly cause painful symptoms in the calf involve the sural nerve and the peroneal nerve posterior to the fibular head. In some cases, ultrasound imaging over the nerve's distribution may reveal scar tissue, ganglions, or other anatomic lesions causing the nerve impingement. Further evaluation with a nerve conduction test or diagnostic imaging (eg, ultrasound, MRI) is needed to make the diagnosis and find the location of the entrapment [42]. (See "Overview of lower extremity peripheral nerve syndromes".)

Peroneal nerve entrapments generally result in motor deficits. The more extreme injuries result in foot drop. Milder injuries may cause varying degrees of weakness in dorsiflexion or eversion of the foot. When the entrapments are caused by a peroneal ganglion, patients may feel tightness in the upper lateral calf behind the fibular head. Weakness in dorsiflexion or eversion helps to distinguish the condition from lateral gastrocnemius injury, which primarily affects plantar flexion strength [60,61].

Sural nerve entrapment is often caused by thickening of the aponeurosis through which the sural nerve passes or scar tissue from a lateral gastrocnemius injury, either of which creates pressure on the sural nerve. More distal entrapment can be caused by a distal gastrocnemius injury, recurrent ankle sprains, pressure from footwear, fifth metatarsal fractures, or overdeveloped calf muscles, as may be seen in bodybuilders [62-64]. The patient with sural nerve entrapment complains of deep, achy posterolateral calf pain along the sural nerve distribution, which encompasses the skin overlying the lateral gastrocnemius and extends towards the lateral malleolus and heel. Pain often increases with percussion along the nerve and with passive dorsiflexion and inversion of the ankle [40,62].

MANAGEMENT

Initial assessment and treatment — The initial treatment for a gastrocnemius, plantaris, or soleus tear is rest until the patient can walk without a limp. If pain is severe, the patient may need a tall walking boot and crutches to assist with ambulation. Heel lifts decrease the stretch of the calf muscles, thereby reducing pain, and may be beneficial initially. The patient should apply ice to the injured area four times per day for 20 minutes at a time until swelling subsides. Nonsteroidal antiinflammatory medication or acetaminophen can be used as needed for pain [1,2]. Compression sleeves worn over the calf (picture 7) help to decrease hematoma formation, especially shortly after the injury. In addition, use of compression sleeves may help speed return to activity [3]. A pneumatic compression device may help reduce acute symptoms if worn regularly [65].

At the initial visit, measure the circumference of the injured calf. This measurement can be used during follow-up visits to assess the resolution of deep swelling. Clinicians facile with ultrasound can image the calf to determine the extent of the injury and the size of any hematoma. Ultrasound can also be used serially to confirm the clinical assessment of healing. Significant calf trauma is a risk factor for acute compartment syndrome and deep vein thrombosis, so patients should be warned about these potential (albeit rare) complications and told to seek medical care immediately if there is any significant increase in their pain or they develop shortness of breath or any other concerning symptom. (See "Acute compartment syndrome of the extremities" and "Clinical presentation and diagnosis of the nonpregnant adult with suspected deep vein thrombosis of the lower extremity".)

There are few trials and no practice guidelines to inform the treatment of calf injuries. The approach described below is based upon the available evidence and the authors' clinical experience managing such injuries. Imaging is optional in most cases, but the authors prefer to use ultrasound for diagnosis, as described above, and to guide management.

The initial decision with a gastrocnemius injury is to determine whether it is severe or mild to moderate. A gastrocnemius strain is considered severe if the patient cannot walk (ie, requires crutches) or the injury is associated with marked swelling or severe pain. For severe injuries, our approach to treatment involves a six-week progression of exercises (described below). However, patients progress at different rates depending upon their age, baseline level of fitness, and other characteristics. At each visit, we perform a clinical assessment to determine subsequent treatment. If the patient has not made sufficient progress, we delay the next steps in our treatment protocol.

For mild to moderate gastrocnemius injuries and for plantaris and soleus injuries, which are at lower risk for delayed healing and complications, we use an accelerated rehabilitation and treatment approach (described below). At the initial visit for patients with milder calf injuries, we observe the patient's walking gait. If there is no limp with walking and pain is minimal, we have the patient add heel lifts to their shoes and don a calf compression wrap and then see if they can do some light jogging at a slow pace without causing significant pain. If they can, we may also ask them to perform a one-legged heel raise on a step. The ability to do this without significant pain indicates a truly mild injury. For confirmed mild injuries, we use the protocol for milder injuries described below, which often allows a return to moderate training in three to four weeks, rather than the six to eight weeks required with more severe injuries. Plantaris injuries in particular heal relatively quickly in most instances. Complete tears of the plantaris tendon can take up to 14 days to heal, but partial tears typically heal within a few days. Even elite athletes often return to sport in less than two weeks with aggressive physical therapy [65].

As soon as the patient can perform a proper heel raise, we have them begin an eccentric exercise program using the Alfredson exercise protocol, which has been studied primarily for the rehabilitation of Achilles tendinopathy. Subsequent studies of Achilles tendinopathy treatment suggest that patients respond equally well to heavy, slow resistance exercise that emphasizes both concentric and eccentric contraction, but further research is needed to confirm this approach. (See "Achilles tendinopathy and tendon rupture", section on 'Rehabilitation using resistance exercise'.)

The initial treatment for popliteal tendinopathy is to avoid downhill walking and jogging. If hyperpronation of the foot is noted, orthotics can be used to prevent this contributing factor. A strength program can be implemented to address any weaknesses identified in the quadriceps, hamstrings, hip flexors, or hip abductors [66,67].

Stretching exercises do not aid healing and should be avoided during rehabilitation; stretching can exacerbate the muscle tears sustained at the time of injury. The use of eccentric strength exercises (eg, Alfredson protocol for Achilles tendinopathy) during the later phases of rehabilitation allows affected muscles to lengthen as effectively as stretching. Patients who have difficulty implementing a home exercise program or who fear reinjury may need additional guidance and encouragement from a physical therapist.

Gait retraining intended to shift from a forefoot to a rearfoot strike reduces the eccentric stress placed on the triceps surae muscles. While some report benefit from this approach, there are no high-quality, controlled studies of gait retraining to treat or prevent calf injury exist [68].

Severe gastrocnemius strain

One-week follow-up — Any patient with a severe gastrocnemius strain should follow up within one week. A gastrocnemius strain is considered severe if the patient cannot walk (ie, requires crutches), or the injury is associated with marked swelling or severe pain. At the first follow-up visit, the clinician determines if swelling has subsided and can repeat an ultrasound examination to assess the size of the tear and any hematoma. Identification of a significant hematoma on ultrasound indicates a need to continue regular icing and use of a compression sleeve (picture 7), and to use a more gradual timetable for introducing full weight-bearing and rehabilitation exercises.

Additional interventions depend upon the patient's symptoms and functional capacity. If possible, the patient should stop using crutches. Once they can walk without a significant limp, the patient should start taking walks three times each day for 10 minutes at a time. If they can perform a heel raise standing on both legs without undue pain, the patient should start performing this exercise regularly, starting with a single set of five to eight repetitions performed with the knees bent, and then repeating this with the knees straight. Gradually, the patient may increase the number of sets and repetitions, assuming these can be performed pain-free, with the ultimate goal of being able to perform three sets of 15 repetitions with the knees straight, and then repeating this with the knees bent. The patient should continue wearing a compression sleeve on the affected calf, using heel lifts, and applying ice four times per day for 20 minutes at a time until swelling subsides.

Stretching exercises do not aid healing and should be avoided during rehabilitation; stretching can exacerbate the muscle tears sustained at the time of injury.

Three-week follow-up — If the patient demonstrates steady improvement in symptoms and function at the three-week follow-up visit, they should begin performing the Alfredson protocol for Achilles tendon injury. This protocol is described in detail separately and summarized in the accompanying table (table 1). (See "Achilles tendinopathy and tendon rupture", section on 'Rehabilitation using resistance exercise'.)

When the patient is able to perform eccentric heel drops for three sets of 15 repetitions on one leg, he or she may begin easy running every other day on a level surface, not to exceed 15 to 20 minutes per session. Additional aerobic exercise can be done on a bicycle or stationary bicycle. Knowledgeable clinicians can monitor a patient's clinical progress with ultrasound.

Six-week follow-up — If the patient continues to demonstrate meaningful progress at the six-week follow-up visit, allow them to start running for longer times and distances, but still on a level surface. As a rule of thumb, increases in running volume should not exceed five minutes per session during a given week, and no more than one additional running day should be added each week. As an example, if the patient ran three times for 20 minutes each session during week one, they could increase this to four times for 25 minutes each session during week two.

The patient should continue to perform heel raise exercises as per the final stage of the Alfredson protocol. Ultrasound can be used to establish if the injury is fully healed. Be sure to observe the patient's running gait to be sure there is no limp or other sign of discomfort. In most cases, 8 to 12 weeks are required for the patient to return to full sports activity. The patient should continue to use heel lifts and compression sleeves during activity for the first three months after their return. Thereafter, we leave it up to the patient whether they wish to continue using them.

Non-severe gastrocnemius injury; plantaris and soleus injuries — Rehabilitation for less severe calf muscle strains is essentially the same as that for more severe muscle injuries but with an accelerated time frame. Stretching exercises do not aid healing and should be avoided during rehabilitation; stretching can exacerbate the muscle tears sustained at the time of injury.

Two-week follow-up — Patients with minor strains are typically able to begin the Alfredson protocol at two weeks. This protocol is described in detail separately and summarized in the accompanying table (table 1). (See "Achilles tendinopathy and tendon rupture", section on 'Rehabilitation using resistance exercise'.)

If the patient is already able to perform three sets of 15 heel raises on a level surface both with the knee straight and with the knee bent, we observe them running. If they have no limp and they have not already started running, we instruct them to begin running 20 minutes daily on a level surface (eg, track) approximately three times each week. Running duration is increased by five minutes each week, and frequency is increased by one day each week.

Four- to six-week follow-up — We prefer to reevaluate patients at four to six weeks or whenever the patient feels they are clinically healed. At that point, we usually repeat an ultrasound examination to see if healing appears to be complete. In addition, we observe the patient's running gait to be sure there is no limp, even with faster strides. If no problems are evident, most patients can return to full activity or competition at six weeks.

Additional treatments — A number of other treatments for posterior calf strain have been used, but they are typically not needed, and the evidence supporting their effectiveness is weak. Case reports suggest that many of the treatments used in acute and chronic tendinopathy have also been used to treat gastrocnemius injury with no clear data demonstrating efficacy [69]. The use of such interventions to treat chronic tendinopathy is discussed separately. (See "Overview of the management of overuse (persistent) tendinopathy".)

Popliteal tendinopathy — Patients with popliteal tendinopathy are encouraged to start jogging on a soft flat surface, such as a track, and to avoid hills. Those who have difficulty recovering from popliteal tendinopathy or strain often benefit from physical therapy, in which they perform non-weightbearing and weightbearing exercises [70].

For milder cases of popliteus tendinopathy, we prescribe a home exercise program featuring modified lunges performed at three different angles. To perform the lunges, the patient starts with the legs spread to shoulders width and the affected leg approximately 18 inches (0.5 m) behind the stance leg. The patient then steps forward on a diagonal approximately 30 degrees toward the affected side five times, followed by stepping directly forward five times, and finally stepping forward across the body toward the unaffected side five times. This total of 15 repetitions (five in each orientation) constitutes one set. At the end of each lunge (ie, forward position), the knee should be flexed approximately 45 degrees; the torso should remain upright throughout the exercise. We ask the patient to perform three sets of this exercise twice daily. When this can be done without difficulty or pain, we have the patient increase the resistance by adding weight to a barbell held on the shoulders. We typically begin with about 20 pounds (approximately 10 kg) and progress to about 60 pounds (approximately 28 kg).

Popliteal artery entrapment — Primary care management of popliteal artery entrapment is to have the patient avoid any inciting exercise and to obtain vascular surgery consultation to determine definitive treatment.

COMPLICATIONS — Complications from a posterior calf muscle injury occur rarely. The most dangerous are acute compartment syndrome and deep vein thrombosis (DVT). These are described in detail separately. Rare complications include myositis ossificans and contracture of the knee and ankle secondary to scar tissue [71]. More common complications include residual calf atrophy and mild weakness. Some individuals complain of chronic tightness or sharp pain that recurs during exercise. (See "Acute compartment syndrome of the extremities" and "Clinical presentation and diagnosis of the nonpregnant adult with suspected deep vein thrombosis of the lower extremity".)

Compartment syndromes involving the leg are caused by far more severe trauma than is typically sustained by laborers or athletes. DVT risk varies among individual patients. Those who are older and have more of the known risk factors for DVT warrant careful consideration. Several case reports describe DVT developing after a calf injury sustained from distance running and other sports activity [57-59]. Some but not all of these individuals have an unsuspected risk factor (eg, undiagnosed malignancy) that contributes to hypercoagulability [58].

Calf muscle injuries typically do not predispose to myositis ossificans, although there are rare case reports [72]. Entrapment of the popliteal artery is dynamic and usually occurs in younger, active individuals, and so is not thought to lead to distal ischemic injury.

RETURN TO SPORT OR WORK — The large majority of calf muscle injuries heal uneventfully. The healing time for posterior calf muscle injuries not requiring surgery ranges from 3 to 16 weeks. Patients take longer to recover if they have complete tears, more extensive muscle injury, large hematomas, or older age [73]. Return to full activity should be determined on the basis of a functional assessment rather than time. Professional athletes working with trainers and physical therapists can reduce the time required to return to play to a median of 13 days [74]. (See 'Severe gastrocnemius strain' above and 'Non-severe gastrocnemius injury; plantaris and soleus injuries' above.)

SOCIETY GUIDELINE LINKS — Links to society and government-sponsored guidelines from selected countries and regions around the world are provided separately. (See "Society guideline links: General issues in muscle and tendon injury diagnosis and management" and "Society guideline links: Muscle and tendon injuries of the lower extremity (excluding Achilles)".)

SUMMARY AND RECOMMENDATIONS

Mechanism of injury – Calf muscle and tendon injuries typically occur during sudden ballistic movements involving the lower extremity, such as sprinting or jumping, in sports where these movements are common, such as tennis, football (soccer), basketball, American football, and running on hills. Calf muscle strains usually occur when the muscles are not warmed up properly or have fatigued significantly during exercise. The medial head of the gastrocnemius plays a major role in generating power when athletes jump or sprint, and injuries of the medial head are relatively common. The soleus, popliteal, and plantaris muscles may also be injured. Injuries of the Achilles tendon are discussed separately. (See 'Epidemiology and risk factors' above and 'Clinical anatomy and biomechanics' above and "Achilles tendinopathy and tendon rupture".)

Gastrocnemius injury – Gastrocnemius injuries typically occur during a sudden push-off when an athlete initiates a sprint or jump, at which point the ankle rapidly moves from plantarflexed to dorsiflexed. A common example is a tennis player who suddenly changes direction to return a shot. Patients typically describe feeling a sudden tearing sensation or pop accompanied by acute pain in the proximal posterior calf that developed while they were running or jumping. Patients have difficulty bearing weight and prefer to keep their ankle in plantarflexion to minimize discomfort. With severe strains, inspection of the patient's posterior calf often shows significant swelling and ecchymosis. Palpation of the proximal calf reveals significant tenderness, usually over the medial head of the gastrocnemius, and possibly a defect in the muscle belly. Active plantar flexion and passive dorsiflexion of the ankle elicit pain. The patient is unable to perform a single leg calf raise, but the Thompson squeeze test (performed to rule out Achilles tendon rupture) is negative (picture 6). (See 'Gastrocnemius strain' above.)

Plantaris injury – The history (sudden ballistic movement involving ankle dorsiflexion) and the examination findings (slight swelling, tenderness, difficulty weightbearing) of plantaris muscle strain are similar to gastrocnemius strain. However, symptoms are generally less severe, and pain and tenderness are located in the region around the mid-Achilles tendon rather than the proximal calf. No muscle or tendon defect is palpable; most patients can dorsiflex and plantarflex their ankle without significant discomfort. (See 'Plantaris strain and tendon injury' above.)

Soleus injury – Soleus strains are usually chronic injuries that develop from overuse, primarily in distance runners. Patients complain of the insidious onset of deep soreness throughout the entire posterior calf. There are no palpable muscle defects. Pain is elicited by flexing the knee and dorsiflexing the ankle simultaneously. Patients with more severe strains have pain with passive testing of the same movements. (See 'Soleus strain' above.)

Popliteal tendinopathy – Popliteal tendinopathy is usually an overuse injury caused by downhill running. Pain from popliteal tendinopathy may present as acute or chronic posterolateral knee pain made worse by walking or running downhill. Tenderness can often be elicited by placing the affected leg in a figure-of-four position and palpating the origin of the popliteal tendon just anterior to the lateral femoral condyle or by performing the Garrick test (described in the text). (See 'Popliteus tendinopathy' above.)

Diagnostic imaging – Neither plain radiographs nor advanced imaging is typically needed to assess muscle strains or tendinopathy of the calf, but ultrasound is useful for confirming the diagnosis and assessing the extent of injury. Common ultrasound findings are described in the text. Advanced imaging is needed to diagnose popliteal artery entrapment. (See 'Diagnostic imaging' above.)

Differential diagnosis – The differential diagnosis for posterior calf pain includes: Achilles tendinopathy or tear; acute compartment syndrome; chronic exertional compartment syndrome; exercise associated muscle cramps; medial tibial stress syndrome (shin splints); osteomyelitis; claudication; deep vein thrombosis; and peripheral nerve entrapment. (See 'Differential diagnosis' above.)

Treatment – The initial management and basic rehabilitation programs for common calf muscle and tendon injuries are described in the text. (See 'Management' above.)

Surgery for an isolated posterior calf muscle or tendon injury not involving the Achilles tendon is rarely necessary. Suspicion for acute compartment syndrome warrants immediate orthopedic consultation. Vascular surgery consultation is needed for popliteal artery entrapment. (See 'Indications for surgical consult or referral' above.)

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Topic 90232 Version 18.0

References

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